I. Field of the Invention
The present invention relates generally to lasers and, more particularly, to a dental laser which is particularly suited for removing dental enamel and dentin, and for cutting soft tissues.
II. Description of the Prior Art
Diseased dental enamel and diseased dentin have traditionally been removed by the dentist by a mechanical drill. On the other hand, diseased soft tissue in the mouth is traditionally removed by cutting with a scalpel, scissors and the like. Both of these methods are uncomfortably painful to the patient, and the results produced have certain drawbacks.
There have, however, been a number of previously known experiments in which teeth have been subjected to laser radiation to determine the alteration, if any, of the physical or chemical properties of the dental enamel. These tests have shown that the hydroxyapatite crystals, that form the enamel, fuse somewhat at the surface when lased and render the enamel more impervious to acids of a type which cause tooth decay.
These previous studies have, however, also concluded that the laser cannot be used to remove tooth decay since the power level necessary for the laser to form an opening in the enamel also significantly heats the tooth and can damage the dental pulp and kill the tooth nerve. For this reason, dental lasers have not been previously used to remove tooth decay or dentin. The lasers that were used previously were operated in different modalities and used different laser materials and were of different wavelengths than those proposed herewith.
In prior U.S. Pat. No. 4,521,194, a method for removing incipient carious lesions from the teeth is disclosed. Such lesions are essentially a surface defect formed on the tooth so that their removal does not require forming an opening in the dental enamel. Furthermore, in that application it was believed that a laser should not be used to form an opening in the dental enamel and dentin for the above-discussed reasons.
U.S. Pat. No. 4,818,230 discloses a method for removing decay that has invaded the dentin as well as removing soft gum tissue in which the peak pulse energy reaches 100 millijoules. In some applications, however, a high energy per pulse is desirable, even if some cooling of the tooth and/or tissues is necessary.